Microbubble creating method using a forming machine

ABSTRACT

A microbubble creating method using a forming machine for creating microbubbles by: installed a microbubble generating member in a mold, feed screw or barrel for enabling a perforated tip of the microbubble generating member to be surrounded by the applied fluid polymer so that when a high pressure high temperature gas is delivered through the perforated tip of the microbubble generating member, microbubbles are created with well mixed with the fluid polymer, and the expected foamed polymer product is thus obtained after cooling.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of application Ser. No. 14/872,858,filed on Oct. 1, 2015.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to foaming technology and moreparticularly, to a microbubble creating method for creating microbubblesin fluid polymer using a forming machine.

2. Description of the Related Art

Foam manufacturing technologies can be classified as mechanical foaming,physical foaming and chemical foaming. In the mechanical foaming,bubbles are created by using an agitator to stir a gas into the fluidpolymer. In the physical foaming, heat produces a low boiling liquidwhich evaporates, thus forming the bubbles. In the chemical foaming, theblowing agent reacts under the influence of heat, releasing gases, whichforms the voids in the fluid polymer beads obtained through thesuspension polymerization.

Further, U.S. Pat. No. 7,264,757 discloses a different technique inwhich a gas delivery pipe is embedded in a feed screw, and a pluralityof microporous breathable blocks is mounted at the front end of the feedscrew. When a high pressure gas is delivered into the gas delivery pipe,the high pressure gas is heated in an indirect manner and then guidedthrough the micro holes of the microporous breathable blocks into thefluid polymer, and thus, the high pressure gas is mixed with the fluidpolymer subject to rotation of the feed screw, and then the mixture ofthe high pressure gas and the fluid polymer is filled into a mold,causing creating of microbubbles in the fluid polymer.

In the aforesaid prior art structures, the microporous breathable blocksare embedded in air vents in the feed screw in flush with the surface ofthe feed screw, thus, the microporous breathable blocks can only be keptin contact with the surface of the fluid polymer and will not besurrounded by the polymer, thus, the supplied gas cannot be fully mixedwith the fluid polymer, resulting in uneven distribution of generatedmicrobubbles in the fluid polymer.

SUMMARY OF THE INVENTION

The present invention has been accomplished under the circumstances inview. It is the main object of the present invention to provide amicrobubble creating method for creating microbubbles in a polymer usinga forming machine, which enhances mixing between the applied gas andfluid polymer, improving uniformity of microbubbles in the fluidpolymer.

To achieve this and other objects of the present invention, amicrobubble creating method in accordance with a first embodiment of theinvention has a microbubble generating member installed in a mold. Themethod is to drive a feed screw in propelling a fluid polymer into themold, enabling the perforated tip of the microbubble generating memberto be surrounded by the fluid polymer; and then to start up amicrobubble generator in generating a high pressure high temperaturegas, enabling the high pressure high temperature gas to createmicrobubbles for mixing with the fluid polymer in the mold when passedthrough the perforated tip of the microbubble generating member, andthus, the expected foamed polymer product with smooth surface and foamedsubcoat is obtained after cooling.

In a second embodiment of the invention, the microbubble generatingmember is installed in a holder member that defines a runner incommunication between the feed screw and a mold. The method is to drivethe feed screw in propelling the fluid polymer, enabling the fluidpolymer to flow through the runner of the holder member and to surroundthe perforated tip of the microbubble generating member in the runner ofthe holder member. Thereafter, start up the microbubble generator togenerate the desired high pressure high temperature gas, enabling highpressure high temperature gas to create microbubbles after passedthrough the perforated tip of the microbubble generating member. Thecreated microbubbles are then mixed with the fluid polymer in therunner, and thus, the expected foamed polymer product with smoothsurface and foamed subcoat is obtained after cooling.

In a third embodiment of the invention, a microbubble generating memberis installed in a locating ring that is mounted at the front end of thefeed screw. This method is to drive the feed screw in propelling thefluid polymer that surrounds the perforated tip of the microbubblegenerating member during flowing. Thereafter, start up the microbubblegenerator to inject a high pressure gas into an air passage of the feedscrew, enabling the high pressure gas to be heated when it is flowingthrough the air passage. After heating, the high pressure gas goesthrough the air passage of the feed screw into the microbubblegenerating member. After the high pressure gas passed through theperforated tip of the microbubble generating member, microbubbles arecreated and mixed with the fluid polymer subject to rotation of the feedscrew.

In a fourth embodiment of the invention, a microbubble generating memberis installed in an output end of a barrel, and a fluid delivery deviceis installed in an opposing input end of the barrel. The method is todrive the feed screw is propelling a fluid polymer from the input end ofthe barrel toward the output end thereof. During propelling, the fluidpolymer is heated, and the perforated tip of the microbubble generatingmember is surrounded by the flowing fluid polymer. At this time, thefluid delivery device is controlled to inject a foaming fluid into thebarrel, enabling the foaming fluid to be mixed with the fluid polymerand heated. Thereafter, start up the microbubble generator to fill ahigh pressure gas into an air passage in the barrel, enabling thesupplied high pressure gas to be heated in the air passage. Afterheating, the high pressure gas goes through the air passage of thebarrel into the microbubble generating member. After the high pressuregas passed through the perforated tip of the microbubble generatingmember, microbubbles are created and mixed with the fluid polymersubject to rotation of the feed screw. Further, the foaming fluid isheated and gradually vaporized during flowing, creating microbubbles inthe fluid polymer, and achieving production of well foamed polymerproduct.

Other advantages and features of the present invention will be fullyunderstood by reference to the following specification in conjunctionwith the accompanying drawings, in which like reference signs denotelike components of structure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic drawing illustrating the flow of a microbubblecreating method in accordance with a first embodiment of the presentinvention.

FIG. 2 is a plain view of a microbubble generator in accordance with thefirst embodiment of the present invention.

FIG. 3 is a schematic drawing illustrating the flow of a microbubblecreating method in accordance with a second embodiment of the presentinvention.

FIG. 4 is a schematic drawing illustrating a check ring stopped at astop flange of a feed screw in accordance with a third embodiment of thepresent invention.

FIG. 5 corresponds to FIG. 4, illustrating the check ring moved awayfrom the stop flange of the feed screw.

FIG. 6 is a schematic structural view of a fourth embodiment of thepresent invention.

FIG. 7 is a schematic structural view of a fifth embodiment of thepresent invention.

FIG. 8 is a schematic structural view of a sixth embodiment of thepresent invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 6, a microbubble creating method in accordance with afirst embodiment of the invention is to be implemented using a foamingmachine 10. The forming machine 10 in this first embodiment of thepresent invention is an extrusion molding machine, comprising a barrel20, a heater 30 mounted around the periphery of the barrel 20 formelting a solid polymer into a fluid polymer 12, a feed screw 40 mountedin the barrel 20 for propelling the fluid polymer 12 toward a mold 14.As illustrated in FIG. 2, the forming machine 10 further comprises amicrobubble generator 50. The microbubble generator 50 can be an aircompressor or any other equivalent air compression device. In thisembodiment, the microbubble generator 50 comprises a pressure cylinder51, a accumulator 52, a plurality of electric heating components 53, anda plurality of microbubble generating members 54. The pressure cylinder51 is adapted for increasing the pressure of air being filled from theoutside. The accumulator 52 is connected to the pressure cylinder 51 forstoring compressed air. The electric heating components 53 are mountedaround the periphery of the accumulator 52 for heating compressed air inthe accumulator 52. The microbubble generating members 54 are connectedto the accumulator 52 for outputting high pressure high temperature gasinto the accumulator 52. Further, each microbubble generating member 54comprises a perforated tip 542 made from, but not limited to, metal,ceramics, or a composite of metal and ceramics. In this firstembodiment, the microbubble generating members 54 are mounted in aninput end 16 of the mold 14 with the perforated tip 542 thereof extendedinto the mold 14.

Referring also to FIG. 1, the microbubble creating method in accordancewith the first embodiment of the invention comprises the steps of:

Step a): Drive the feed screw 40 to propel the fluid polymer 12 into theinside of the mold 14, enabling the perforated tips 542 of themicrobubble generating members 54 to be immersed in the fluid polymerand is surrounded by the fluid polymer 12 in the mold 14.

Step b): Start up the microbubble generator 50 to generate high pressurehigh temperature gas, forcing high pressure high temperature gas to goout of the perforated tips 542 of the microbubble generating members 54and to further create microbubbles that are then mixed in the fluidpolymer 12 inside the mold 14. After cooling, the expected foamedpolymer product with smooth surface and foamed subcoat is thus obtained.

Referring to FIG. 3, a microbubble creating method in accordance with asecond embodiment of the invention can be implemented using an extrusionmolding or injection molding machine. This second embodiment issubstantially similar to the aforesaid first embodiment with theexception that each microbubble generating member 54 is obliquelymounted at a holder member 55 that defines a runner 552 in communicationbetween the feed screw 40 and the mold 14 for enabling a fluid polymer12 to pass; each microbubble generating member 54 comprises a perforatedtip 542 with extended into the runner 552 so that microbubbles generatedby each microbubble generating member 54 can be filled into the fluidpolymer 12 at a low pressure; the microbubble generator 50 furthercomprises a static mixer 56 mounted in the runner 552 of the holdermember 55 between the microbubble generating member 54 and the mold 14for enabling generated microbubbles to be well mixed with the fluidpolymer 12. Thus, the microbubble creating method in accordance withthis second embodiment of the invention comprises the steps of:

Step a): Drive the feed screw 40 to propel the feeding fluid polymer 12.When the fluid polymer 12 is being propelled into the runner 552 of theholder member 55, the perforated tips 542 of the microbubble generatingmembers 54 will be to be immersed in the fluid polymer and surround thefluid polymer 12 and be propelled through the runner 552 of the holdermember 55 into the mold 14.

Step b): Start up the microbubble generator 50 to generate high pressurehigh temperature gas forcing high pressure high temperature gas to goout of the perforated tips 542 of the microbubble generating members 54and to further create microbubbles that are then mixed in the fluidpolymer 12 in the runner 552 subject to the functioning of the staticmixer 56, and then delivered with the fluid polymer 12 toward the insidethe mold 14. After cooling, the expected foamed polymer product withsmooth surface and foamed subcoat is thus obtained.

Referring to FIG. 4, a microbubble creating method in accordance with athird embodiment of the invention can be implemented using an injectionmolding machine. This third embodiment is substantially similar to theaforesaid first and second embodiments with the exception that eachmicrobubble generating member 54 is mounted in a locating ring 57 thatis mounted at a front end of the feed screw 40 in such a manner that theperforated tip 542 of each microbubble generating member 54 protrudesover the surface of the feed screw 40; the microbubble generator 50further comprises an air compressor (not shown) adapted for providinghigh pressure gas to each microbubble generating member 54; a staticmixer 56 is disposed at a front side relative to the feed screw 40.Thus, the microbubble creating method in accordance with this thirdembodiment of the invention comprises the steps of:

Step a): Drive the feed screw 40 to propel the fluid polymer 12,enabling the fluid polymer 12 to surround the perforated tips 542 of themicrobubble generating members 54 during delivery.

Step b): Start up the air compressor of the microbubble generator 50 toprovide high pressure gas into an air passage 42 in the feed screw 40,enabling high pressure gas to be heated by the heater 30 when flowingthrough the air passage 42.

Step c): After heating, high pressure gas goes through the air passage42 of the feed screw 40 into the microbubble generating members 54 tocreate microbubbles after passed through the perforated tips 542 of themicrobubble generating members 54, enabling created microbubbles to beprimarily mixed with the fluid polymer 12 subject to rotation of thefeed screw 40 and then the static mixer 56 will mix the microbubbleswith the fluid polymer 12 when injection again.

Further, the feed screw 40 comprises a stop flange 44 disposed near afront end thereof and abutted against the locating ring 57. Further, acheck ring 58 is attached to the front end of the feed screw 40, asshown in FIG. 5. When the feed screw 40 is being rotated to propel thefeeding material, the check ring 58 will be forced to move away from thestop flange 44 of the feed screw 40, enabling the barrel 20 toaccommodate sufficient high pressure high temperature gas and sufficientvolume of the fluid polymer 12. When injecting the fluid polymer 12 intothe mold 14, the check ring 58 will be stopped at the stop flange 44 ofthe feed screw 40 to prevent a reverse flow of the fluid polymer 12,avoiding clogging of the perforated tips 542 of the microbubblegenerating members 54 by micromolecules of the fluid polymer 12.

Referring to FIG. 6, a microbubble creating method in accordance with afourth embodiment of the invention can be implemented using an extrusionmolding machine. This fourth embodiment is substantially similar to theaforesaid first embodiment with the exception that the microbubblegenerating members 54 are mounted in the output end 22 of the barrel 20with the perforated tips 542 of the microbubble generating members 54extended inside into the barrel 20; further, the microbubble generatingmembers 54 are connected to an air compressor (not shown), constitutingthe microbubble generator 50. Thus, the microbubble creating method inaccordance with this fourth embodiment of the invention comprises thesteps of:

Step a): Drive the feed screw 40 to propel the fluid polymer 12,enabling the fluid polymer 12 to be heated by the heater 30 and theperforated tips 542 of the microbubble generating members 54 immerse inthe fluid polymer and to be surrounded by the fluid polymer 12 as thefluid polymer 12 is being propelled from the input end 21 of the barrel20 toward the output end 22 of the barrel 20.

Step b): Start up the microbubble generator 50 to provide high pressuregas into an air passage 23 in the barrel 20, enabling high pressure gasto be heated by the heater 30 when flowing through the air passage 23.

Step c): After heating, high pressure gas goes from the air passage 23of the barrel 20 through a pipeline 59 into the microbubble generatingmembers 54 to create microbubbles after passed through the perforatedtips 542 of the microbubble generating members 54, enabling createdmicrobubbles to be mixed with the fluid polymer 12 during rotation ofthe feed screw 40.

The microbubble generator 50 further comprises a fluid delivery device60 mounted in the input end 21 of the barrel 20 and extend inside intothe barrel 20. Thus, in the aforesaid Step a), the fluid delivery device60 is controlled to inject a foaming fluid into the barrel 20, enablingthe supplied foaming fluid to be mixed with the fluid polymer 12 andheated by the heater 30. When the foaming fluid is vaporized,microbubbles are created in the fluid polymer 12 to mate with themicrobubbles generated by the microbubble generating members 54,achieving production that is well foamed polymer product.

It is to be noted that, as shown in FIG. 7 and FIG. 8, it is notimperative to have the microbubble generating members 54 and the fluiddelivery device 60 be concomitantly installed. In actual application,the microbubble generating members 54 and the fluid delivery device 60can be selectively installed. For example, in the application exampleshown in FIG. 6, the microbubble generating members 54 and the fluiddelivery device 60 are concomitantly installed; in the applicationexample shown in FIG. 7, only the microbubble generating members 54 areinstalled; in the application example shown in FIG. 8, the fluiddelivery device 60 is installed, and the aforesaid microbubblegenerating members 54 are eliminated. In any application example,sufficient microbubbles can be created to achieve excellent foaming. Ofcourse, both the microbubble generating members 54 and the fluiddelivery device 60 can be concomitantly installed to achieve optimaleffects.

In conclusion, the microbubble creating method of the invention is toinsert microbubble generating members 54 into the applied fluid polymer12. When compared to conventional techniques, the inventionsignificantly increases the contact area between the microbubblegenerating members 54 and the fluid polymer 12, thereby increasing theamount of gas that enters the fluid polymer 12 and enabling generatedmicrobubbles to be evenly distribute in the fluid polymer 12.

Although particular embodiments of the invention has been described indetail for purposes of illustration, various modifications andenhancements may be made without departing from the spirit and scope ofthe invention. Accordingly, the invention is not to be limited except asby the appended claims.

What is claimed is:
 1. A microbubble creating method for creatingmicrobubbles in a polymer using a forming machine, said foaming machinecomprising a feed screw and a microbubble generator, said microbubblegenerator comprising a microbubble generating member, said microbubblegenerating member comprising a perforated tip, the microbubble creatingmethod comprising the steps of: a) driving said feed screw to propel afluid polymer into a mold, enabling said perforated tip of saidmicrobubble generating member to be immersed in the fluid polymer and besurrounded by said fluid polymer; and b) starting up said microbubblegenerator to generate a high pressure high temperature gas, enablingsaid high pressure high temperature gas to create microbubbles formixing with said fluid polymer in said mold when passed through saidperforated tip of said microbubble generating member.
 2. The microbubblecreating method as claimed in claim 1, wherein said microbubblegenerator further comprises a pressure cylinder, an accumulatorconnected to said pressure cylinder and an electric heating componentattached to said accumulator; said microbubble generating member isconnected to said accumulator.
 3. The microbubble creating method asclaimed in claim 1, wherein said mold comprises an input end; saidmicrobubble generating member is mounted near said input end of saidmold.
 4. The microbubble creating method as claimed in claim 3, whereinsaid microbubble generator further comprises a pressure cylinder, anaccumulator connected to said pressure cylinder and an electric heatingcomponent attached to said accumulator; said microbubble generatingmember is connected to said accumulator.
 5. The microbubble creatingmethod as claimed in claim 1, wherein said microbubble generatorcomprising a holder member, said holder member comprising a runnerdisposed in communication between said feed screw and said mold, saidmicrobubble generating member being mounted in said holder member, saidmicrobubble generating member comprising a perforated tip with extendedinto said runner, for the step a), driving said feed screw to propelsaid fluid polymer into said runner of said holder member toward saidmold, enabling said perforated tip of said microbubble generating memberto be immersed in the fluid polymer and be surrounded by said fluidpolymer.
 6. The microbubble creating method as claimed in claim 5,wherein said microbubble generator further comprises a static mixermounted in said runner of said holder member between said microbubblegenerating member and said mold for mixing said microbubbles with saidfluid polymer during step b).
 7. The microbubble creating method asclaimed in claim 6, wherein said microbubble generator further comprisesa pressure cylinder, an accumulator connected to said pressure cylinderand an electric heating component attached to said accumulator; saidmicrobubble generating member is connected to said accumulator.
 8. Themicrobubble creating method as claimed in claim 5, wherein saidmicrobubble generator further comprises a pressure cylinder, anaccumulator connected to said pressure cylinder and an electric heatingcomponent attached to said accumulator; said microbubble generatingmember is connected to said accumulator.